Hot water supply heater

Abstract

To detect a water level in a heating tank, even in the case where a reference electrode cannot be disposed in the heating tank.SOLUTION: A water supply heater 1 includes: a heating tank 69 provided in the middle of a heating circuit B; and a control substrate 79. The heating tank 69 includes: a resin casing 69E; and two water level electrodes 90 which are two water level electrodes 90 (first water level electrode 90A and second water level electrode 90B) disposed in the casing 69E, and in which heights of lower ends are different from each other. The control substrate 79 detects a water level in the heating tank 69 on the basis of presence / absence of the current flowing in the water level electrodes 90. The heating circuit B includes a metal piping member (connection piping 93) at least in one part. To the control substrate 79, electric wires 91A, 91B extending from each of the water level electrodes 90 are connected, and an electric wire 91C for piping member fixed to the piping member is connected, in the water supply heater 1.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The technology disclosed in this specification relates to a hot water heater. [Background technology]

[0002] Hot water heaters equipped with a hot water circuit and a heating circuit that is connected to an underfloor heating terminal installed in the house to form a circulating heating circuit and a heating tank in the middle of the heating circuit are generally available (see, for example, Patent Document 1). The tank functions as a buffer that absorbs the expansion of hot water in the circulating heating circuit, and also functions as a water injection part that injects water into the circulating heating circuit.

[0003] Inside such a heating tank, two water level electrodes, Hi and Lo, are provided at different heights, and a reference electrode is provided at a lower position than the water level electrodes. The two water level electrodes and the reference electrode are electrically connected to a control board, and a power cord, earth wire, etc. are connected to this control board. In such a hot water heater, the potential of the reference electrode is set as the reference potential, and by observing the potentials of the Hi and Lo water level electrodes relative to this reference potential, the approximate water level in the tank can be detected. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2007-024495 A Summary of the Invention [Problem to be solved by the invention]

[0005] By the way, due to the nature of detecting the water level, it is preferable to install the reference electrode below the two electrodes Hi and Lo. However, depending on the size, shape, and internal structure of the heating tank, it may be difficult to install the reference electrode inside the heating tank. This specification discloses a technique that can detect the water level in a heating tank even when a reference electrode cannot be disposed inside the heating tank. [Means for solving the problem]

[0006] The hot water heater of the present disclosure comprises a heating tank provided midway through a heating circuit, and a control board, the heating tank comprising a resin casing and two water level electrodes arranged within the casing, the two water level electrodes having different lower end heights, and the control board detecting the water level in the heating tank based on an electrical signal from the water level electrodes.In this hot water heater, the heating circuit at least partially includes metal piping members, and electric wires extending from each of the water level electrodes are connected to the control board, as well as electric wires for the piping members that are fixed to the piping members. Effect of the Invention

[0007] According to the above configuration, even if a reference electrode cannot be disposed inside the heating tank, the water level inside the heating tank can be detected. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is a front view of the hot water heater according to the first embodiment. [Diagram 2] FIG. 2 is a front view of the hot water heater without the front cover. [Diagram 3] FIG. 3 is a schematic circuit diagram of the hot water heater. [Figure 4] FIG. 4 is a schematic diagram of the heating tank and the control board. [Diagram 5] FIG. 5 is a partial front view of the hot water heater excluding the front cover. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] [Description of the embodiments of the present disclosure] First, embodiments of the present disclosure will be listed and described.

[0010] (1) The hot water heater of the present disclosure comprises a heating tank provided in the middle of a heating circuit, and a control board, the heating tank comprising a resin casing and two water level electrodes arranged within the casing, the two water level electrodes having different lower end heights, and the control board detecting the water level in the heating tank based on an electrical signal from the water level electrodes, the heating circuit at least partially including a metal piping member, and the control board is connected to electric wires extending from each of the water level electrodes and to which piping member electric wires fixed to the piping members are connected.

[0011] In the hot water heater described in (1) above, the electric wire for the piping member is connected to the metal piping member that constitutes the heating circuit. The heating circuit is filled with hot water during normal use, so that the piping member and the water level electrode can be electrically connected via the hot water. Therefore, even if a reference electrode cannot be disposed in the heating tank, the water level in the heating tank can be detected by detecting the presence or absence of a current flowing between the piping member and the water level electrode.

[0012] (2) In the hot water heater described in (1) above, a connection port is formed at the bottom of the heating tank, and a connection pipe that forms part of the piping member and directs hot water in the heating circuit to the heating tank or discharges hot water in the heating tank is connected to the connection port, and an electric wire for the piping member may be connected to the connection pipe.

[0013] Since the connecting pipe is relatively close to the heating tank, it is possible to reduce the resistance from the connection part of the electric wire for the piping components to the water level electrode in the heating tank. Also, since it is close to the heating tank, the heating tank and the connecting pipe are almost always filled with hot water without interruption. Therefore, by adopting the configuration of the hot water heater described in (2) above, it is possible to maintain good conduction from the connection part of the electric wire for the piping components to the water level electrode, and the water level in the heating tank can be detected with high accuracy.

[0014] [Details of the embodiment of the present disclosure] An embodiment of the present disclosure will be described with reference to Figures 1 to 5. The present disclosure is not limited to these examples, but is defined by the claims, and is intended to include all modifications within the meaning and scope of the claims.

[0015] (1) Overall structure of the hot water heater An overview of a hot water heater 1 according to the first embodiment will be described with reference to Fig. 1. The hot water heater 1 has a hot water supply function of heating supplied tap water and supplying hot water to the outside, and a heating function of supplying hot water to a radiator installed indoors or under a floor to heat the indoors or floor. The hot water heater 1 has a front cover 72. The front cover 72 has an exhaust port 73 that houses an exhaust pipe 16 (see FIG. 3) described later, an air intake port 74 for taking in outside air, and the like.

[0016] As shown in FIG. 2, the hot water heater 1 includes a housing 70, an inner body 2 housed in the housing 70, a control board 79, and the like. The housing 70 includes a box-shaped housing main body 71 having an opening 71A on the front surface, and a front cover 72 (see FIG. 1) that closes the opening 71A of the housing main body 71. The housing body 71 comprises a bottom plate 71B located on the lower side when viewed from the front, a left side plate 71C located on the left side when viewed from the front, a right side plate 71D located on the right side when viewed from the front, a top plate 71E located on the upper side when viewed from the front, and a rear wall 71F located on the rear side.

[0017] The inner body 2 is equipped with a hot water supply combustion chamber 4, a heating combustion chamber 5, a hot water supply primary heat exchanger 11, a heating primary heat exchanger 13, a hot water supply secondary heat exchanger 12, a heating secondary heat exchanger 14, and an exhaust hood 15. The inner body 2 is partitioned into left and right parts by a partition member 3 (see FIG. 3 ) described later, with the hot water supply combustion chamber 4, the hot water supply primary heat exchanger 11, and the hot water supply secondary heat exchanger 12 provided on the right side, and the heating combustion chamber 5, the heating primary heat exchanger 13, and the heating secondary heat exchanger 14 provided on the left side.

[0018] As shown in Fig. 3, the hot water supply / heating apparatus 1 has a hot water supply circuit A, a heating circuit B, and a bath circuit C. The heating circuit B at least partially includes a metallic piping member.

[0019] The hot water heater 1 has a hot water supply combustion chamber 4 and a heating combustion chamber 5 separated by a partition member 3 within an inner body 2, and a burner 6. The burner 6 includes a hot water supply burner 6A disposed at the bottom of the hot water supply combustion chamber 4, and a heating burner 6B disposed at the bottom of the heating combustion chamber 5. Each combustion chamber 4, 5 is provided with an ignition plug 8 and a flame rod 9. A combustion fan 10 is provided at the bottom of the inner body 2 to supply combustion air to each burner 6A, 6B.

[0020] A hot water supply primary heat exchanger 11 and a hot water supply secondary heat exchanger 12 through which the combustion exhaust gas of the hot water supply burner 6A passes are provided at the upper part of the hot water supply combustion chamber 4. A heating primary heat exchanger 13 and a heating secondary heat exchanger 14 through which the combustion exhaust gas of the heating burner 6B passes are provided at the upper part of the heating combustion chamber 5. Each secondary heat exchanger 12, 14 is housed in an exhaust hood 15 provided at the upper part of the inner body 2. The exhaust hood 15 is formed with an exhaust pipe 16 that discharges the combustion exhaust gas that has passed through each secondary heat exchanger 12, 14.

[0021] A gas pipe 17, to which gas piping from the outside is connected, is connected to a gas inlet provided on the bottom plate 71B of the housing 70. Gas branch pipes 18, 18, ... branching off from the gas pipe 17 are connected to each of the hot water supply burners 6A and the heating burner 6B, and each gas branch pipe 18 is provided with a gas solenoid valve 19 for opening and closing the gas flow path. In addition, a main gas solenoid valve 20 and a gas proportional valve 21 are provided from the upstream side on the gas pipe 17 before branching.

[0022] A water supply pipe 22, which is connected to a water inlet 78 of the bottom plate 71B, is connected to the inlet of the heat absorption pipe of the hot water secondary heat exchanger 12. From the upstream side, the water supply pipe 22 is provided with a strainer 23 equipped with a drain plug, a hot water supply water volume sensor 24 that detects the volume of water flowing through the water supply pipe 22, a hot water supply inlet thermistor 25 that detects the inlet water temperature, and a water volume control valve 26 that controls the volume of water flowing through the water supply pipe 22.

[0023] The outlet of the heat absorption tube is connected to the inlet of the heat transfer tube of the hot water primary heat exchanger 11, and the outlet of the heat transfer tube is connected to the hot water outlet of the bottom plate 71B. The hot water outlet pipe 27 is provided with a hot water heat exchanger thermistor 28 that detects the outlet temperature from the hot water primary heat exchanger 11, and a hot water outlet thermistor 29 that detects the hot water temperature from the fixture downstream of the hot water heat exchanger thermistor 28. A bypass pipe 30 that bypasses the hot water primary and secondary heat exchangers 11 and 12 is connected between the upstream side of the hot water outlet thermistor 29 in the hot water outlet pipe 27 and the downstream side of the water volume control valve 26 in the water supply pipe 22, and the bypass pipe 30 is provided with a water distribution valve 31 that controls the bypass flow rate. Thus, within the housing 70, a hot water supply circuit A is formed in which water from the water supply pipe 22 passes through the hot water supply secondary heat exchanger 12 and the hot water supply primary heat exchanger 11 in that order, is heated by heat exchange with the combustion exhaust gas from the hot water supply burner 6A, and is then discharged from the hot water supply pipe 27.

[0024] On the other hand, the heating return pipe 32, which is connected to the heating return port 76 of the bottom plate 71B, is connected to the inlet of the heat absorption pipe of the heating secondary heat exchanger 14. The heating return port 76 is connected to the downstream end of the pipe extending from the high-temperature radiator 33 and the low-temperature radiator 34 outside the hot water heater 1. The high-temperature radiator 33 is, for example, a heating blower that blows warm air into the room. The low-temperature radiator 34 is, for example, a floor heater. The outlet of the heat absorption pipe of the heating secondary heat exchanger 14 is connected to the intermediate pipe 35 (intermediate pipes 35A, 35B). The intermediate pipe 35 is provided with a heating tank 69 and a heating circulation pump 36. A mounting bracket 94 is attached to the intermediate pipe 35A. The heating tank 69, the intermediate pipe 35A, and the mounting bracket 94 will be described later.

[0025] The downstream end of the intermediate piping 35 is connected to the heating low-temperature outgoing pipe 38 and the inlet of the heat transfer pipe of the heating primary heat exchanger 13. A thermal valve 39 is disposed downstream of the heating low-temperature outgoing pipe 38, and branches off the heating low-temperature outgoing pipe 38. The downstream end of the thermal valve 39 is a heating low-temperature outgoing port 77. The heating low-temperature outgoing port 77 is connected to the low-temperature radiator 34.

[0026] The outlet of the heat transfer tube of the heating primary heat exchanger 13 is connected to the heating high-temperature forward pipe 40. The downstream end of the heating high-temperature forward pipe 40 is a heating high-temperature forward port 75 provided in the bottom plate 71B. The heating high-temperature forward port 75 is connected to the high-temperature radiator 33. The heating high-temperature forward pipe 40 is provided with a heating high-temperature thermistor 41. The heating high-temperature forward pipe 40 and the heating return pipe 32 are connected by a bath heating pipe 42. The bath heating pipe 42 is provided with a reheating flow control valve 43. A heating bypass pipe 44 that bypasses the heating primary and heating secondary heat exchangers 13 and 14 is connected between the upstream side of the heating tank 69 in the intermediate pipe 35 and the heating high-temperature forward pipe 40, and the heating bypass pipe 44 is provided with a bypass thermo-operated valve 45 that controls the bypass flow rate.

[0027] Therefore, in the heating circuit B, the hot water heated in the heating secondary heat exchanger 14 circulates to the heating return pipe 32 via the intermediate piping 35, the heating tank 69, the heating low-temperature forward pipe 38, and the low-temperature radiator 34, and also flows into the heating primary heat exchanger 13 via the intermediate piping 35. The hot water heated in the heating primary heat exchanger 13 returns to the heating return pipe 32 via the heating high-temperature forward pipe 40 and the high-temperature radiator 33, and circulates to the heating primary heat exchanger 13 via the heating secondary heat exchanger 14, the intermediate piping 35, and the heating tank 69.

[0028] The bath circuit C is provided with a bath heat exchanger 46 into which the bath heating pipe 42 is inserted. The inlet of the bath heat exchanger 46 is connected to a bath return pipe 47 connected to the bath return port of the bottom plate 71B. The bath return port is connected to the bathtub 49 via an external bath return pipe 48. A bath circulation pump 50 is provided downstream of the bath return pipe 47. A bath return thermistor 51 that detects the bath return temperature is provided upstream of the bath circulation pump 50. A water flow switch 52 and a water level sensor 53 are provided downstream of the bath circulation pump 50. The outlet of the bath heat exchanger 46 is connected to a bath supply pipe 54 that is connected to the bath supply port of the bottom plate 71B. The bath supply port is connected to the bathtub 49 via an external bath supply pipe 55. A bath supply thermistor 56 that detects the bath supply temperature is provided in the bath supply pipe 54.

[0029] A drop pipe 57 is connected between the downstream side of the bypass pipe 30 in the hot water outlet pipe 27 and the upstream side of the bath circulation pump 50 in the bath return pipe 47. A drop water solenoid valve 58 that opens and closes the drop pipe 57 and a bath water volume sensor 59 that detects the amount of water flowing through the drop pipe 57 are provided on the upstream side (hot water outlet pipe 27 side) of this drop pipe 57. The drop pipe 57 makes it possible to supply hot water heated in the hot water supply circuit A to the bathtub 49. Three check valves 60, 60, 60 are provided downstream of the bath water volume sensor 59. A cutoff valve 61 is connected between these check valves 60. This cutoff valve 61 is connected to a drain pipe 62 connected to an overflow outlet provided in the bottom plate 71B and an introduction pipe 63 connected to the downstream side of the strainer 23 in the water supply pipe 22. When the internal pressure of the hot water in the drop pipe 57 increases due to the back pressure from the bath return pipe 47 and becomes greater than the back pressure from the inlet pipe 63, the cut-off valve 61 discharges the hot water that flows back from the drop pipe 57 through the drain pipe 62 to the overflow outlet. In this way, a bath circuit C that circulates hot and cold water in the bathtub 49 is formed by the bath heat exchanger 46, the bath supply pipe 54, the bath return pipe 47, etc.

[0030] A neutralizer 64 for neutralizing drain generated in the hot water secondary heat exchanger 12 and the heating secondary heat exchanger 14 is provided within the housing 70. This neutralizer 64 is connected to a drain receiver 66 provided on the bottom surface of the exhaust hood 15 via a drain inlet pipe 65, and is also connected to the drain pipe 62 of the cut-off valve 61 via a drain outlet pipe 67. The neutralizer 64 is provided with a water level electrode 68 for detecting the water level.

[0031] The control board 79 will be described with reference to Fig. 2. A control unit such as a CPU, a microcomputer (a so-called microcomputer), and an FPGA (Field Programmable Gate Array) as well as various electronic components are mounted on the control board 79. The control board 79 receives detection signals from thermistors, sensors, etc. and operates various valves to control the outlet hot water temperature, fill bathtub 49 with hot water, and control the heating temperature. Although not shown, the hot water heater 1 is equipped with a remote control etc. that is communicatively connected to the control board 79.

[0032] (2) Heating tank The heating tank 69 will be described with reference to Fig. 4. The heating tank 69 is intended to prevent the pipes and the like constituting the heating circuit B from being damaged when the liquid (water in this embodiment) circulating through the heating circuit B is heated and expands.

[0033] The heating tank 69 includes a resin casing 69E and two water level electrodes 90 (a first water level electrode 90A and a second water level electrode 90B) disposed within the casing 69E. The two water level electrodes 90 are provided so as to penetrate the ceiling wall 69A of the casing 69E. The two water level electrodes 90 are each rod-shaped, and the heights of their lower ends (in other words, the vertical positions of their lower ends) are different from each other. Specifically, the second water level electrode 90B extends below the first water level electrode 90A. The first water level electrode 90A is connected to the control board 79 via a first electric wire 91A (an example of an electric wire). The second water level electrode 90B is connected to the control board 79 via a second electric wire 91B (an example of an electric wire).

[0034] Two connection ports 69C, 69D are formed in a bottom wall 69B (an example of a lower part of a heating tank) of the heating tank 69. Intermediate pipe 35A is connected to connection port 69C. Intermediate pipe 35B is connected to connection port 69D. Although omitted in FIG. 4, a heating low-temperature thermistor 37 (see FIG. 3) is provided on the bottom wall 69B of the heating tank 69.

[0035] (3) Intermediate piping The intermediate pipe 35A will be described with reference to Fig. 5. The intermediate pipe 35A is mainly made of resin, but includes some metal pipe members. The intermediate pipe 35A has a connection pipe 93 that forms part of the metal pipe member, and the connection pipe 93 is connected to a connection port 69C of the heating tank 69. Hot and cold water in the heating circuit B is led out from the connection pipe 93 to the heating tank 69.

[0036] (4) Mounting bracket 5, a description will be given of the mounting metal fitting 94 attached to the connection pipe 93. The mounting metal fitting 94 is a metal member for fixing the piping component electric wire 91C (see FIG. 4) to the connection pipe 93. The mounting metal fitting 94 is attached to the intermediate pipe 35A by brazing. 4, a piping member electric wire 91C is fixed to the mounting fixture 94. The other end of the piping member electric wire 91C is connected to the control board 79.

[0037] (5) Detection of water level in heating tank Detection of the water level in the heating tank 69 will be described with reference to Fig. 4. The water level in the heating tank 69 is detected in three stages: low, medium, and high. High is a state in which the water level in the heating tank 69 is higher than the bottom end of the first water level electrode 90A, medium is a state in which the water level is lower than the bottom end of the first water level electrode 90A and higher than the bottom end of the second water level electrode 90B, and low is a state in which the water level is lower than the bottom end of the second water level electrode 90B.

[0038] The piping component electric wire 91C is connected to one end of a first current path 100 formed on the control board 79. A power source 101 is connected to the first current path 100. The negative side of the power source 101 is grounded. The other end of the first current path 100 branches into a second current path 102 and a third current path 103. A current sensor 104 is provided on the second current path 102. A current sensor 105 is provided on the third current path 103.

[0039] The first electric wire 91A connected to the first water level electrode 90A is connected to the second current path 102. When the water level is high, the first water level electrode 90A and the metal connecting pipe 93 are electrically connected by the hot or cold water, and a current flows between the connecting pipe 93 and the first water level electrode 90A. The control board 79 (more specifically, the control unit mounted on the control board 79) uses a current sensor 104 to detect the presence or absence of current flowing between the connecting pipe 93 and the first water level electrode 90A (in other words, whether or not current is flowing in the second current path 102). In the following explanation, a state in which current is flowing is referred to as "on," and a state in which current is not flowing is referred to as "off."

[0040] The second electric wire 91B connected to the second water level electrode 90B is connected to the third current path 103. When the water level is high or medium, the second water level electrode 90B and the metal connecting pipe 93 are electrically connected by the hot or cold water, and a current flows between the connecting pipe 93 and the second water level electrode 90B. The control board 79 uses a current sensor 105 to detect the presence or absence of a current flowing between the connecting pipe 93 and the second water level electrode 90B (in other words, whether or not a current is flowing in the third current path 103).

[0041] The method of detecting whether or not a current is flowing is not limited to the method using a current sensor, and can be appropriately selected. For example, a resistor may be provided in the second current path 102 (or the third current path 103), and a voltage sensor may be provided in parallel with the resistor. Then, the control board 79 may determine that a current is flowing when a potential difference occurs before and after the resistor.

[0042] As shown in Table 1 below, the control board 79 determines that the water level is high when the first current sensor 104 is on, determines that the water level is medium when the first current sensor 104 is off and the second current sensor 105 is on, and determines that the water level is low when both the first current sensor 104 and the second current sensor 105 are off. [Table 1]

[0043] (6) Effects of the embodiment In the hot water heater 1 according to the first embodiment, a piping member electric wire 91C is connected to a metal piping member that constitutes a heating circuit B. The heating circuit B is filled with hot water during normal use, so that the piping member and the water level electrode 90 can be electrically connected via the hot water. Therefore, even if a reference electrode cannot be provided in the heating tank 69, the water level in the heating tank 69 can be detected by detecting the presence or absence of a current flowing between the piping member and the water level electrode 90.

[0044] According to the hot water heater 1, a connection port 69C is formed at the bottom of the heating tank 69, and this connection port 69C is connected to a connection pipe 93 which forms part of a metallic piping component and which directs hot water in the heating circuit B to the heating tank 69, and an electric wire 91C for the piping component is connected to this connection pipe 93. Because the connection pipe 93 is relatively close to the heating tank 69, it is possible to reduce the resistance from the connection part of the piping component electric wire 91C to the water level electrode 90 in the heating tank 69. Also, because it is close to the heating tank 69, the heating tank 69 and the connection pipe 93 are almost always filled with hot water without interruption. Therefore, by adopting the configuration of the hot water heater 1, it is possible to maintain good conduction from the connection part of the piping component electric wire 91C to the water level electrode 90, and the water level in the heating tank 69 can be detected with high accuracy.

[0045] <Other embodiments> (1) In the above embodiment, the case has been illustrated in which the piping member electric wire 91C is connected to the connection pipe 93 constituting part of the intermediate pipe 35 that delivers hot and cold water in the heating circuit B to the heating tank 69. In contrast, a connection pipe may be provided in the intermediate pipe 35B from which the hot and cold water in the heating tank 69 is discharged, and the piping member electric wire 91C may be connected to the connection pipe. In other words, the piping member electric wire 91C may be connected to the intermediate pipe 35A or to the intermediate pipe 35B.

[0046] (2) In the above embodiment, a case has been described where a metallic connection pipe 93 is connected to the connection port 69C. However, a resin connection pipe may be connected to the connection port 69C, and a part of a metallic piping member may be connected to the connection pipe. The mounting fixture 94 may then be fixed to a part of the metallic piping member. Even when a resin connection pipe is present between them, the water level electrode 90 and the mounting fixture 94 are electrically connected to each other via hot water and cold water. [Explanation of symbols]

[0047] 1: Hot water heater 69: Heating tank 69C: Connection port 69D: Connection port 69E: Casing 79: Control board 90(90A, 90B): Water level electrode 91A: First electric wire (an example of an electric wire) 91B: Second electric wire (an example of an electric wire) 91C: Wire for piping components 93: Connection pipe B: Heating circuit

Claims

1. A heating tank provided in the middle of the heating circuit; A control board; Equipped with The heating tank comprises a resin casing and two water level electrodes disposed in the casing, the two water level electrodes having lower ends at different heights, and the control board detects the water level in the heating tank based on the presence or absence of a current flowing through the water level electrodes. The heating circuit includes at least a portion of a piping member made of metal, The hot water heater, wherein electric wires extending from each of the water level electrodes are connected to the control board, and electric wires for piping members fixed to the piping members are connected to the control board.

2. The hot water heater according to claim 1, A hot water heater and heater in which a connection port is formed at the bottom of the heating tank, and a connection pipe that forms part of the piping member and that draws hot water in the heating circuit to the heating tank or discharges hot water in the heating tank is connected to the connection port, and an electric wire for the piping member is connected to the connection pipe.

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